If you want to come to Ireland for less than 3 months, you should apply for a short stay 'C' visa. You should apply for this type of visa if you want to come to Ireland as a tourist or to visit someone, for a business meeting, or to attend a short course. You cannot stay for longer than 3 months on a 'C' visa.
If you are travelling to Ireland and you are not a citizen of the UK, Switzerland, or a country in the European Economic Area (the EU plus Norway, Iceland and Lichtenstein), you may need to apply for a visa. An Irish visa is a certificate placed on your passport or travel document that allows you to travel to Ireland.
You should apply for this type of visa if you want to come to Ireland as a tourist or to visit someone, for a business meeting, or to attend a short course. You cannot stay for longer than 3 months on a 'C' visa. You must leave Ireland and apply for another visa if you want to return.